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Collinear resonant ionization spectroscopy for neutron rich copper isotopes. ISOLDE INTC-P-316. Spokespersons : G. Neyens, M.M. Rajabali, K.U. Leuven Local contact: K.T. Flanagan, Univ . Manchester.
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Collinear resonant ionization spectroscopy for neutron rich copperisotopes ISOLDE INTC-P-316 Spokespersons: G. Neyens, M.M. Rajabali, K.U. Leuven Local contact: K.T. Flanagan, Univ. Manchester K.U. Leuven, Belgium: M.L. Bissel, I. Budincevic, R. Garcia-Ruiz, G. Neyens, J. Papuga, M.M. Rajabali University of Manchester, U.K.: K.T. Flanagan, J. Billowes, B. Cheal, K.M. Lynch, T.J. Proctor ISOLDE, CERN, Geneva, Switzerland: T.E. Cocolios, H.A. Khozani, K.M. Lynch, B. March, S. Rothe MPI furQuantenoptik, Garching, Germany: M. Hori, H.A. Khozani, A. Soter University of Tokyo, Tokyo, Japan: T. Kobayashi IPN-Orsay, France: F. Le Blanc, D. Verney New York University, New York, USA: H.H. Stroke MainzUniversity, Germany: K. Wendt Belgian Research Initiative on eXotic nuclei
GENERAL MOTIVATION Studymagicity of Z=28 and N=50 in 78Cu ( = 78Ni + 1p -1n) ? Studyevolution of single particlelevelstowards78Ni Measure spins and moments of 76,77,78Cu 73 71 75 77 69 K.T. Flanagan et al., PRL103, 142501 (2009) odd-Cu g..s spins and moments K.T. Flanagan et al., Phys. Rev. C 82, 041302(R) (2010) 72,74Cu g.s. spins and moments ( parity, wave function) U. Koester et al., PRC84, 034320 (2011) 77Cu g.s. spin and magnetic moment -n Search forlong-livedisomers in 76,77,78Cu and measuretheir spin and moments possiblespin-gapisomer in 78Cu, related to neutron in nd5/2 p 78Ni
SPECIFIC MOTIVATION Availabledecayspectroscopyinformation on 76,78Cu isotopes is notconclusive ! Needfirmground state spin assignments to allowinterpretation of spectroscopy data (including Ni motherisotopesand Zn daughterisotopes) b-decay J. Van Roosbroeck et al. Phys. Rev. C71, 054307(2005) J.A. Winger et al., PRC 42, 954 (1990) 2 long-livedstates b-decayingisomerornot ? b-decay b-decay b-decay b-decay Theory ISLS C. J. Gross et al. Acta Phys. Pol. B40, 447 (2009). J. Van Roosbroeck et al. Phys. Rev. C71, 054307(2005). N. Patronis et al. Phys. Rev. C80, 034307(2009). J.A. Winger et al. ActaPhys. Pol. B39, 525(2008). N. A. Smirnova et al. Phys. Rev. C69,044306(2004) U. Koster et al. Phys. Rev. C84,034320(2011)
EXPERIMENTAL TECHNIQUE: CRIS Collinear Resonance Ionization Spectroscopy 1/2 32P3/2 3/2 7/2 m < 0 3/2 32S1/2 most intense line 5/2 Combine the best of twomethods: - collinear laser spectroscopy high resolution ( ~ 50 MHz) BUT low detection efficiency: 1 photon /30.000 ions reducenon-resonantphoton background usingbunchedbeams (ISCOOL) Need > 104ions/s Photoncounts 5/2 74Cu, I=2 Measure: • μ • Qs • δ<r2> • spin 325 nm
EXPERIMENTAL TECHNIQUE: CRIS Collinear Resonance Ionization Spectroscopy Combine the best of twomethods: - resonanceionisationspectroscopy high detection efficiency (ions), low background BUT low resolution (ifdonein-source) Need < 10 ions/s detectresonantlyexcitedions 77Cu – in-source Measure: • μ • (spin) U. Koester et al., PRC84, 034320 (2011)
EXPERIMENTAL TECHNIQUE: CRIS Collinear Resonance Ionization Spectroscopy Combine the best of twomethods: - collinear laser spectroscopy narrowlinewidthdue to acceleration to 40 keV + resonanceionisationspectroscopy high detection efficiency, low background Need < 10 ions/s 355 nm 77Cu – CRIS 4P1/2 Assumed 300 MHz linewidth due to frequencytripplingafterpulseddyeamplification 4P3/2 244 nm 249 nm Measure: • μ • Qs • δ<r2> • spin
EXPERIMENTAL TECHNIQUE: CRIS Collinear Resonance Ionization Spectroscopy Pulsed ion beamfrom ISCOOL two-stepresonanceionisation intocontinuum mcp-detector + b-decay + g-decay detection station 355 nm 4P1/2 4P3/2 244 nm 249 nm CW pulsedamplified laser forresonantexcitation Pulsed laser beamforionization Cu-I 2S1/2
Cu PRODUCTION RATES Limit foropticaldetection ~ 104ions/mC Limit for CRIS ~ 10 ions/mC • 78Cu measuredyield =200 ions/mC accessiblewith CRIS method • 79Cu extrapolatedyield= few ions/mC
BEAM TIME request • 2 shiftswithstable63,65Cu prior to the run • 12 shiftswithradioactive Cu isotopes To measure the hyperfinestructure of 76,77,78Cu relative to that of 69,71Cu and 72Cu spins, magneticmoments, quadrupolemoments, isotopesshifts
244 nm: m and <dr2> • 249 nm: Q (low precision)
Honma 56Ni core Brown Sieja and Nowacki 48Ca core PRC81, 061303(R),2010
Consequences for spectroscopy – shell model tests Assign spins to levels in 71,73,75Cu: Stefanescu et al. Phys. Rev. Lett. 100, 112502 (2008) Daugas et al., Phys. Rev. C C 81, 034304 (2010) Theories reproduce lowering of 5/2- in 75Cu 73 71 75 77 69 interactionstartingfrom a 56Ni core (Flanagan et al., PRL 103, 142501,2009) Brown, Lisetsky jj44b interactionstartingfrom a 48Ca core (Sieja and Nowacki, PRC81 061303(R),2010) • The ½ level is loweredbyopenening N=28 shell • The 3/2- is pushed up by ~ 1 MeVin 79Cu
m = -1.347 mN FWHM=60 MHz m = -1.068 mN FWHM=300 MHz m = -0.4 mN